Oh I am a numpty! There's a fuse, in the rear fuse box, FB10 I think called "Alarm System Horn" or some such. Take that out, no noise. Duh, job done. Actually, it didn't matter, because the garage had to order a new alarm horn, that being the problem again or so they believe, and they couldn't get one until tomorrow. However I've asked them to leave it disconnected and I'll take it back after the holiday. Absolutely no risk of irritating the neighbours while we're away now. Trevor